'Half the size of Atlantic': James Webb Space Telescope suggests exoplanet LHS 1140 b could have a massive ocean

Produced by: Tarun Mishra

Credit: B. Gougeon/Université de Montréal

Water Search as the Key to Habitability

The search for habitability in the universe focuses on the presence of water. Liquid water, rather than ice or vapor, is crucial for the potential evolution of life as we know it.

Discovery of LHS 1140 b

The James Webb Space Telescope (JWST) recently identified exoplanet LHS 1140 b, which may host a temperate water ocean about half the size of the Atlantic, making it a prime candidate for habitability studies.

Exoplanet in the Habitable Zone

LHS 1140 b orbits a red dwarf star in the constellation Cetus, 48 light-years from Earth. It resides in the habitable zone, where conditions may support liquid water, earning it the nickname "Goldilocks zone."

Potential Atmosphere Detected

For the first time, researchers have detected hints of an atmosphere on a rocky or ice-rich exoplanet in the habitable zone, possibly indicating conditions that could support liquid water.

Credit: Jorge Lillo-Box

Historical Interest  in LHS 1140 b

LHS 1140 b has been under investigation for some time, with previous studies suggesting it could be a water world. The JWST's advanced capabilities have now provided stronger evidence to support this hypothesis.

Credit: NASA

Confirmation of  Exoplanet Type

The JWST data ruled out the possibility of LHS 1140 b being a mini-Neptune, confirming it as a super Earth, which is larger than Earth and potentially water-rich, enhancing its habitability prospects.

Calmer Host Star

Unlike the TRAPPIST-1 system, where stellar activity complicates habitability assessments, LHS 1140 b's host star is less active, making it easier to study the exoplanet's atmosphere without interference.

Credit: NASA

Mass and Composition Analysis

JWST data suggests LHS 1140 b's mass could be composed of 10% to 20% liquid water. The exoplanet might resemble a snowball with a liquid ocean on the side facing its star, similar to how the Moon shows only one face to Earth.

Future Observations Required

While the findings are promising, further studies with the JWST are needed to confirm the presence of liquid water and assess LHS 1140 b's potential for habitability. Researchers view this as a significant step in the ongoing search for extraterrestrial life. The pre-print version of the study detailing these findings can be accessed on arXiv.